Localization of Multiple Leak Sources Using Acoustic Emission Sensors Based on MUSIC Algorithm and Wavelet Packet Analysis

Multiple leak sources may occur in a large pressure

vessel that contains corrosive materials or has been in use for a

long period of time. Although a variety of leak localization

methods have been proposed in previous studies, they are capable

of locating only a single leak source. Methods for simultaneous

localization of multiple leak sources are desirable in practical

applications. To address this issue, a novel method using acoustic

emission (AE) sensors in conjunction with MUltiple SIgnal

Classification (MUSIC) algorithm and wavelet packet analysis is

proposed and experimentally assessed. High-frequency AE

sensors are assembled into a linear array to acquire signals from

multiple leak sources. Characteristics of the leak signals are

analyzed in the frequency domain. Wavelet packet analysis is

deployed to extract useful information about the signals from the

frequency band of 50 kHz - 400 kHz. The MUSIC algorithm is

applied to identify the directions of the leak sources through a

space spectrum function. Leak sources are located based on the

directions identified by the AE sensor array placed at different

locations. The performance of the proposed method is evaluated

through experimental tests on a stainless steel flat plate of 100 cm

×100 cm×0.4 cm. The results demonstrate that the method is

capable of locating two leak holes. In addition, the localization

accuracy depends on the leaking pressure. It is demonstrated that

the two leak holes are located within two small areas, respectively,

which are 25.12 cm2 for leak hole 1 and 1.96 cm2 for leak hole 2.